writemasks, abs, log + tests
writemasks, abs, log + tests

- Mask::operator!
- implement and test abs
- add WriteMaskedVector to implement write masked operations (e.g.  ++vec(mask) )
- fix Gather of structs on 32bit architectures where sizeof(Struct)
  doesn't have to be a multiple of sizeof(double)
- implement approximate logarithm for SSE::Vector<float/double>
- add support for setting the fuzzyness for double comparison
- tests for write masks
- tests for math functions

mattkretz/virtest,mattkretz/virtest